Garden TIps: Insects, disease pose problems for plums

Q: We have a plum tree that seems to be in bad health. There is some type of fungus growing on the branches and trunk of the tree. It did produce plums, but they were small and hard. The tree also had sap coming out at the base of it. What could be the problem? -- Mike Carlson

A: Cankers and insect borers can affect plum trees.

A canker is a dead sunken spot on the stem, branches or base of the tree. Canker affects trees that are under stress from poor soil conditions or drought.

Sap coming from a wound on the base of the tree, absent any borer holes, indicates the tree is diseased and eventually may have to be cut down. This is especially true for plum trees.

If the tree has borers and you catch the problem early enough, you can save the tree. Remove the sap to see whether you have borer holes. If you do, check with your local nursery or garden center to see what insecticide is good for killing borers.

The Extension Service has a publication on disease control of fruit trees that you might want to pick up.

Q: I have a juniper tree that is about 15 feet tall. I believe it has blight this year. One day, I noticed that the top half started to turn brown, and within two days the whole top of the tree was completely brown. What do you think is the problem? -- Candice Nash

A: Several things can cause juniper trees to turn brown. They include spider mites and drought. I believe you might have spider mites because of how fast the tree turned brown. Spider mites are small insects that feed on the sap of many of our landscape plants. As they suck the juices from the plant, the infested part turns brown. Spider mite populations can build up so fast that the damage can seem to appear overnight.

We are having problems with spider mites this year because we have had dry weather. You can try washing them off with a stream of water. Also, they can be controlled with a miticide insecticide. Check with your local nursery or garden center for a product that controls mites. If there is severe damage on your plant, the branches may die. Also keep a check on your other plants for signs of spider mites. Look for discoloration of the foliage. Make sure your plant has good drainage. You can prevent severe damage if you catch this in time.

E-mail your questions to bleigh1@utk.edu. Include your name and where you live. For more gardening information, call the Tipton County Extension office at (901) 476-0231 or the Shelby County Extension office at (901) 752-1207. Booker T. Leigh is the Extension director for Tipton County.